Sonar Application

Sonar ApplicationDSP Project:Good Evening Submitted By

Thajid Ibna Rouf UdayID: 021 121 102MD. Ashif JardaryID: 021 122 039

Supervisor:Haider Adnan KhanDept of EEEUnited International University

What is SONAR !SONARisanabbreviation for SOUNDNAVIGATIONAndRANGINGSonar is a technique that usessoundpropagation (usually underwater, as insubmarine navigation) tonavigate, communicate with or detect objects on or under the surface of the water, such as other vessels.History of SonarAlthough some animals have used sound for communication and object detection for millions of years, use by humans in the water is initially recorded by Leonardo Da Vinci in 1490: a tube inserted into the water was said to be used to detect vessels by placing an ear to the tube.

In the 19th century an underwater bell was used as an ancillary to lighthouses to provide warning of hazards.

The use of sound to 'echo locate' underwater in the same way as bats use sound for aerial navigation seems to have been prompted by the Titanic disaster of 1912. The world's first patent for an underwater echo ranging device was filed at the British Patent Office by English meteorologist Lewis Richardson, one month after the sinking of the Titanic

During World War I the need to detect submarines prompted more research into the use of sound.

Who else uses sonar Actually animals use echolocation and that is actually where we learned the techniqueBats, whales, and dolphins are some of the best known animals to use echolocation

Uses of SonarWarfare

Anti-submarine warfare- A conventional hull mounted sonar is used

Torpedoes-Modern torpedoes are generally fitted with an active/passive sonar. This may be used to home directly on the target.

Mines-Mines may be fitted with a sonar to detect, localize and recognize the required target

Submarine navigation-Submarines rely on sonar to a greater extent than surface ships as they cannot use radar at depth.

Underwater security-Sonar can be used to detect frogmenand otherscuba divers.

Uses of SonarCivilian applications

Fisheries-Acoustic technology is especially well suited for underwater applicationssince sound travels farther and faster underwater than in air.

Net location-The net sounder is an echo sounder with a transducer mounted on the headline of the net rather than on the bottom of the vessel.

Ship velocity measurement-Sonars have been developed for measuring a ship's velocity either relative to the water or to the bottom.

Uses of SonarScientific applications Biomass estimation Wave measurement Water velocity measurement Bottom type assessment Bottom topography measurement Sub-bottom profiling Synthetic aperture sonar Parametric sonar

How Sonar WorksSonar is simply making use of an echo. When an animal or machine makes a noise, it sends sound waves into the environment around it. Those waves bounce off nearby objects, and some of them reflect back to the object that made the noise. It's those reflected sound waves that you hear when your voice echoes back to you from a canyon. Whales and specialized machines can use reflected waves to locate distant objects and sense their shape and movementHow Sonar Works

Process to Find DistanceSends a pulseTime of the echos return is measuredCan calculate the distance travelled by knowing the speed of sound in water

Process to Find Distance

Measuring distanceLet r = distance of the object.t = time between the transmission and reception.v = velocity of sound (in water).Distance, h = v*t/2

Signal Processing in SonarUsually, the reflection (echo) is very noisy. Also, the sound intensity decreases due to the distance traveled. There can be sound from separate source (interference) as well. So the quality of the echo is very poor. Therefore, the received signal is filtered to remove the noise and interference (sounds from other sources).

Signal Processing in SonarFinally, the filtered signal is cross-correlated with the original transmitted signal to identify the similarity and the lag (distance).Here , x(n) is the transmitted signal and y(n) is the received signal ,y2(n) is filtered signal.

Visualization through Transmitted and Received Signal%% sonar application close allload('x.mat');load('y.mat'); %% FFT of the transmitted signal x(n)Nx=length(x);nx=0:Nx-1;wx=(nx/Nx)*2 - 1; Xf=fft(x);Xf=fftshift(Xf);Xf_mag = abs(Xf);Xf_ph = angle(Xf); subplot(3,1,1)plot( nx, x)title('Transmitted signal')subplot(3,1,2)plot(wx, Xf_mag)title('Magnitude Spectrum, |X(w)|')subplot(3,1,3)plot(wx, Xf_ph)title('Phase Spectrum')

Visualization through Transmitted and Received Signal%% FFT of the transmitted signal y(n) Ny=length(y);ny=0:Ny-1;wy=(ny/Ny)*2 - 1; yf=fft(y);yf=fftshift(yf);yf_mag = abs(yf);yf_ph = angle(yf); figure,subplot(3,1,1)plot( ny, y)title('Received signal')subplot(3,1,2)plot(wy, yf_mag)title('Magnitude Spectrum, |X(w)|')subplot(3,1,3)plot(wy, yf_ph)title('Phase Spectrum')

Fdatool Design

Visualization through Transmitted and Received Signal[b,a]=sos2tf(SOS,G); %this is iir filter coefficient finding functiony1=filter(b,a,y); Ny1=length(y1);ny1=0:Ny1-1;figure(3)subplot(2,1,1)plot(ny,y),title('received signal'),xlabel('n'),ylabel('amplitude of y');subplot(2,1,2)plot(ny1,y1),title('received signal after filtering'),xlabel('n'),ylabel('amplitude of filtering signal');

Visualization through Transmitted and Received Signal%% frequency response & impulse response of band pass filter figure(4)freqz(b,a);figure(5)impz(b,a)

Visualization through Transmitted and Received SignalImpulse response of band pass filter

Visualization through Transmitted and Received Signal%% fast fourier transform of filtered signal y1f=fft(y1);y1f=fftshift(y1f);y1f_mag=abs(y1f);y1f_ph=angle(y1f);wy1=(ny1/Ny1)*2-1;figure(6)subplot(2,1,1)plot(wy1,y1f_mag),title('received signal`s fourier transform'),xlabel('w'),ylabel('magnitude of filtered signal');subplot(2,1,2)plot(wy1,y1f_ph),title('received signal`s fourier transform'),xlabel('w'),ylabel('phase of filtered signal');

Visualization through Transmitted and Received Signal%% performing cross-correlation [xfo,nxfo]=sigfold(x,nx);[r,l]=conv_m(xfo,nxfo,y1,ny1);figure(7)plot(l,r),title('after cross correlation'),xlabel('l'),ylabel('amplitude');

Calculation of DistanceAs Fs is provided we can easily find total time(t)Now finding, t=L./FsIn our project Fs=5000 HzSo ,t=6576/5000=1.3152And finally we can easily find our expected distance by using the following formulaDistance=(t*velocity)./2In our project velocity of sound in water =1481 m/sSo, the distance =(10.8500*1481)/2= 973.9056 meters

Conclusion By this experiment, Weve learn how to measure a distance of any object from source in water . To detect the distance of object we use SONAR because, in water the velocity of Sound is better than microwave . This is an excellent project for us . Weve learn a lot of things from this project. Now we can easily solve any simple problem of SONAR systemReference http://en.wikipedia.org/wiki/Sonarhttp://oceanservice.noaa.gov/facts/sonar.htmlhttp://www.exploratorium.edu/theworld/sonar/sonar.htmlhttp://macartney.com/news/many-uses-sonar

Thank You